1. Field of the Invention
The present invention relates to a domestic bread proofing oven and a method for controlling the oven. Upon activation for a rapid proofing operation, the oven of the invention will heat-up to a first temperature, before cooling and being maintained at a second lower temperature. This procedure allows for proofing of uncooked dough, selectively at an increased rate, without killing the yeast.
2. Discussion of the Prior Art
Generally, the process for making bread at home includes mixing yeast, sugars, flower, liquids, and salt in proper proportions to form a dough, which is then repeatedly kneaded and allowed to rise for a precise period of time. Traditionally, the ingredients were mixed by hand and the dough was set aside to rise. Following the rising period, the dough is then baked and cooled.
Once the yeast has been added, the dough begins to rise. This period is called proofing. During proofing, the yeast is growing and fermenting as it is consuming the added sugar. During this fermenting process, the yeast emits carbon dioxide and other gasses which bubble through the dough causing the dough to expand, or rise.
Because proofing often takes an extended period of time, and health reasons prevent leaving the dough unrefrigerated for as long as it takes for bread to proof, proofing is often conducted in a cooled environment such as a refrigerator. But yeast fermentation is slowed considerably when in a cooled environment. Therefore, placing the unproofed bread inside a refrigerator extends the proofing time extensively.
Similarly, conventional ovens cannot be used to proof dough because the lowest available temperature settings will kill the yeast before proofing has been completed. Specifically, it is desired to maintain the dough at a temperature just high enough to allow the yeast to properly grow, while neither cooking the dough nor killing the growing yeast, e.g. approximately 110xc2x0 F. (43xc2x0 C.). Unfortunately, traditional ovens are not provided with such settings.
Recently, machines have been developed which automates the entire bread making process. Users simply place the correct measurements of ingredients into the machine and the machine takes over. Automatically, the ingredients are mixed forming a dough, and the dough is permitted to rise. Once a specific amount of rising time has elapsed, the baking procedure begins. In order to make the cooking process as easy as possible, all of the ingredients are placed inside the cooking chamber. While this may make the bread making procedure significantly faster and simpler, the resulting bread is often inferior in quality.
Automatic bread making machines, while often convenient and easy to use, have additional limitations. Primarily, users are required to have a separate appliance in their kitchen, which only has limited uses. Because most kitchens have limited counter space, these automatic bread makers must be stored away when not use. This means that whenever someone wants to use one of these automatic bread makers, they need to retrieve the machine from wherever it is stored, carry it to the kitchen and, when finished, return it to storage. For homes with limited storage space, finding adequate storage is also a problem. In any event, it would be preferable to avoid the need for a dedicated domestic bread machine. Instead, it would be beneficial to specifically adapt a conventional oven for use in optimally proofing uncooked bread, preferably in a manner in which actually reduces the overall operation time.
The present invention is particularly directed to a method and apparatus for proofing bread without requiring a separate appliance by incorporating a proofing methodology into a conventional oven. The oven of this invention includes a bread proofing option which is activated via a separate control sequence. Selecting the bread proofing option activates a respective control algorithm which operates the existing heating element(s) inside the oven to allow proofing of dough therein.
In accordance with a preferred rapid proofing embodiment of the invention, the control algorithm of the invention activates the heating element(s) of the oven. First, the temperature of the oven cavity is elevated beyond that which required to proof the dough. Advantageously, this temperature overshoot allows for the quick activation of the yeast without baking the dough. Activation of the yeast starts the fermentation process, which causes the yeast to emit carbon dioxide. It is the carbon dioxide that causes the bread to rise. The remainder of the proofing process is best carried out at a temperature lower than that necessary to initially activate the yeast. Therefore, once the activation temperature is reached, the proofing oven of the invention automatically lowers the temperature of the oven cavity to a temperature high enough to proof the bread rapidly, without baking the dough.
The algorithm of the invention controls the heating element to maintain this lower temperature for a specified time. Accordingly, this lower temperature is achieved by cycling on and off the heating element at the lower temperature. This prevents the dough from reaching a temperature on either side of a target temperature. This cycling on and off of the heating element, and hence the maintenance of the oven cavity temperature, is accomplished by lowering the heat output of the heating element.
When the oven of the invention is an electric oven, the heat output can be controlled by varying the voltage to one or more of the available heating elements. During normal baking, the lower or bake heating element is energized with 240 volts. When the same heating element is used during the proofing process, 120 volts is used. This lower voltage prevents the heating element from reaching temperatures necessary to bake the unproofed dough.
Once proofing, is complete, the dough is ready for baking. At this point, the normal operations of the oven can be utilized. By providing this process in an oven which is capable of both proofing and baking the dough, the number of appliances necessary to make the bread is reduced and the overall operational efficiency and convenience is enhanced.